Mini-ITX SE/86 Mod

Marcus Brooks—12 July 2004
Modified 24 July 2004

I am not an x86 kind of guy, but ever since I saw the Mini-ITX board in Yoshi's rocket mod on the Screensavers (on G4TechTV), I've had a hankering to cram one into my old Mac SE/30's case. Fifteen years ago, my SE/30 cost about three grand (at a 50% developer discount). She was hot stuff then, and served me well for many years, but eventually Moore's law (and a dead floppy controller) consigned her to the closet. It's a Faustian bargain to reanimate my old Mac at the cost of her Motorola soul, but what the heck, it's just a computer.

DANGER: This mod involves handling electronic parts that can kill you even after the unit is unplugged. Before any modding, please read a good safety guide, like the RepairFAQ safety page.

I've seen one other “SE/30” mod on the web (The "Wraith SE/30"), but I found it disappointing. That one hardly resembles the original item, so why bother? I decided if I was to do an SE/30 mod, it would have to look as much like the real thing as possible.

I was too lazy to strip the case to a bare shell. Instead, I kept the original chassis to hold everything together. It's built like a tank. The original 3.5-inch floppy and hard drives were mounted in a heavy cage on top of the chassis. I left out the cage entirely. Instead, I mounted my CD-RW drive between a couple of angle aluminum rails. Then I applied ample globs of epoxy putty to the rails and mashed it all into place behind the front grill (where it fits surprisingly well). After scratching my head some, I did the same with the hard drive, gluing its rails right on top of the CD-RW drive. (Why not?)

The CD-RW drive I used was a new LITE-ON model, standard size except for its depth (front-to-back). Size isn't why I bought that model, but I'm not sure I could've done without the extra space in back.

The CD-RW drawer face involved some careful hacking with a #11 hobby-knife sawblade I got from Micro-Mark sometime in the last century. Epoxy putty (of course) holds it on. For the button, I ground teeth into the end of a bit of aluminum arrow shaft to make a plug-cutter of sorts, then drilled the plug out from the back. A little more epoxy and carving and the plug fit just right in its own hole. A bit of electrician's tape holds it on from the back—just the right mix of give and tenacity. After getting it all working, I did a fill and blend job on the CD door outline to hide it better—the pictures you see are a “before and after” set.

The HDD light presented a problem. The original SE/30 had only one LED, for the hard disk. There was no such thing as “Standby” then, so it was easy to tell the machine was on. The new motherboard has LED outputs for both power and hard disk status. I thought about using a two-lead bicolor LED, but that would require a bit of logic to switch signals.

I finally hit on the idea of simply stuffing in one LED behind the other. I whittled down an ordinary green LED (for “power”) to glue in between the leads of the original yellow HDD LED. This makes a very effective four-lead coaxial green/yellow bicolor LED. The original LED was mounted to the hard drive cage, so I just hacked out the LED mounting part and glued it behind the lens on the case front with a glob of epoxy putty.

Looking at the dual-purpose LED as I use the machine, I find it easy to imagine it always worked like that.

I selected a VIA EPIA-V8000 for the motherboard because it has the speed and features I want at a low price. I mounted the new motherboard to the bottom of the chassis, in the same plane where the original motherboard lived. I used a 4” angle grinder with a cutting disc to open up the necessary clearance holes in the chassis. Now that's what I call hacking! Naturally the mini-ITX board doesn't fit the keyways that held the original, so I built mounting posts out of #6-32 all-thread rod, tee-nuts, and epoxy putty.

My power supply is a 200-watt Mini-ATX type, ostensibly an Emachines replacement. There are purpose-built Mini-ITX supplies that might work better, but they're nowhere near as cheap. I mounted the new supply pretty much in the same place where the old one lived. I had to do a fair amount of cutting to make everything fit, make the wires come out where I wanted, and allow for decent air circulation. I hacked off the old supply's AC input jack and switch (and surrounding metal) then glued them in behind the new supply so they protrude from the case back as before. I wired the old jack directly to the new supply. The new supply's AC input jack is unused (and inaccessible).

I kept the old AC switch, but wired it only to the CRT. The new motherboard has inputs for an ACPI power button as well as a reset switch. I decided to control these with the SE/30's original “Programmer's Switch” feature. This is a little plastic piece that clipped onto the SE/30's side and actuated reset and break (debug) switches on the original motherboard. In theory, these buttons would never be used except by programmers, so Apple made it a user-installed in-box option.

I removed the switches from the old motherboard (they were glued on, so a blowtorch was involved) and glued them inside the case. I shortened the actuator “fingers” on the plastic part to suit the new switch position. I made the front button power and the back one reset. This moves the original reset function, but I like the most-used button in front. Maybe I'll change the markings sometime.

If your SE/30 has lost its programmer's switch, you can mount any ol' button switch in a spare hole on the back of the case for power. I don't think the reset button is really necessary.

Although the computer itself might do without a case fan in such a tall enclosure, the CRT puts out a lot of heat. The original case fan would have encroached on my CRT installation, so I decided to try one of the newer processor fans, a 2-inch model picked up randomly at a Goodwill store. I hacked the new fan's mounting plate out of the hefty Analog board that filled one side of the old SE/30.

The original design used clever ways to avoid mounting any electrical parts on the back, probably because there was no economical way to connect them. Here you can see part of my (labor intensive) solution.

To get wiring to the case fan and power/reset switches, I stole a 10-pin Molex connector from the old Analog board. I glued the socket half to the chassis (being careful not to glue the halves together). After the glue cured, I pre-wired the other connector half, plugged it into the mounted half, put on some strategic globs of epoxy putty, and assembled the case. (Of course I cut off the connector latch first!)

After the second half cured, I had a perfectly matched case connector. The connector is near a case screw so it is held together tightly, and it isn't as hard to separate as I feared.

By the way, extracting sockets from the Molex plug (for rewiring) is a pain. It involves shoving in tiny shims on both sides of each socket and yanking the wire. I used a wheel on my Dremel to whittle shims out of a paperclip.

Of course I had to have a real CRT in my mod—no expensive, confusing, funny-looking LCD for me! The SE/30's original CRT was strictly black-and-white, with no grays, and I have no idea how I might connect it to the new motherboard. I wanted something I could just plug into the VGA port.

It turns out 9-inch VGA CRTs are still used in point-of-sale applications. The color models I've seen are too deep for the SE/30 case, but the monochrome one I got fits just fine. I found mine at a local computer salvage shop, but be patient. Most people either laugh or look confused if you ask for a 9-inch VGA monitor.

The monitor I got only supports 640x480 video. Apparently some support up to 800x600. I consider myself in the market for one of those, but I intend to be patient. For one thing, 640x480 is a little more usable than I thought, especially since I discovered that KDE lets you drag any part of a window by holding the Alt key. I haven't quite mastered the art of making Linux boot nicely in 640x480, but it's OK once I fake it through to KDE.

The new CRT has a different mounting depth than the old one, so I glued in some #10-32 all-thread posts for it. Each post has a backwards tee-nut (with locknut) to provide an adjustable-depth backer for the tube's mounting ears.

The CRT's circuit board mount is kind of haphazard. (Hey, I thought it was a temp.) I just bolted it to pieces of modified aluminum channel, which in turn are epoxied to a pair of N-struts bent from welding rod. There really isn't enough room for the board to be comfortable. If I get another CRT I'll try putting its board in on one side or the other.

Like I said, I wanted to be able to just plug the CRT into the motherboard's VGA socket. The simplest way to do this was pull the cable out the back of the case and plug it in, so that's what I did. I had to modify the choke on the cable some to get it through the SE/30's expansion slot opening, but it works.

The dumbest thing I did in the whole mod was to try shortening the VGA cable by splicing some out of the middle. Royal pain. Worst is that the video kept going loopy and I redid the splice a couple of times before I realized the header sockets on the board end had worked loose. I should have just cut that end off and re-wired the connector.

I considered the CRT for this mod to be an aesthetic sine qua non, and I do expect it to come in handy. But most of the time I'll be using my big monitor via a KVM switch. One nice thing about that big choke on the VGA cable is it makes a handy block for holding the cable steady when it's stowed. Sometime maybe I'll try to rig up an internal/external VGA switch. Yeah, right.

The CRT I got has brightness and contrast controls, whereas the one-bit-deep SE/30's display only needed brightness. Luckily, I was able to rig the new knobs to face each other and pook out of the same opening in the case where the big old brightness knob lived. This arrangement works better than I could have hoped. I even swapped the leads on one pot so they both turn the right way.

Last, and probably least: audio. The SE/30's original speaker came out to make room for the CD-RW drive, and anyway the new board's audio out isn't amplified. I'm still deciding what to do for real, but for now I've just gutted one half of an old amplified speaker set and stuffed it in wherever it would fit. I shrink-wrapped the circuit board, of course. Power is from the 5V line on a spare power connector. This speaker's magnet is kind of big and was skewing the CRT, so I moved it as close to center as possible. The plus side is that the magnet holds the speaker in place while I decide what to do with it.

Audio is wired directly to the left channel (I just picked one). One channel is OK for system sounds, but probably not games or music (especially Beatles tracks, I've noticed). Someday I might rig up a real mixing amp with a switch and volume and all that, but I seriously doubt I'll ever put more than one speaker in this thing.

That's all for now. Ave atque vale!